Chomsky (2004) proposed that the operations previously called Merge and Move are essentially identical; i.e., external merge and internal merge, respectively. Empirically, this leads us to expect the existence of phenomena that require some type of merge but do not specify the type. Alexiadou and Anagnostopoulou (1998), in turn, suggested a further unity among types of internal merge—that phrasal movement and head movement are essentially identical. This paper argues in favor of both Chomsky's and Alexiadou and Anagnostopoulou's proposed unification of diverse phenomena. On the basis of material from Czech, a T-Extension Condition (TEC), superficially similar to the EPP, is proposed. The condition requires the tree to be extended past T. This extension is indifferent to the distinction between head movement and phrasal movement, and also to the distinction between internal and external merge. In addition (in contrast to the EPP), the TEC, when satisfied by external merge, is insensitive to whether T or the merging element projects.